Mar 3, 2015 - In patients with synchronous stage IV colorectal cancer who receive up-front modern combination chemotherapy, immediate colon surgery to remove the primary tumor is seldom necessary, according to research presented at the annual meeting of the American Society of Clinical Oncology, held from May 29 to June 2 in Orlando, Fla. These findings accompanied several other studies presented at the conference focusing on treatment of gastrointestinal cancers.